In the course of the handling or use of rolls of paper or other continuous web material wound about a core, the relatively heavy weight of the wound material frequently occasions damage to the core. The core material, typically paperboard or cardboard, is not particularly rigid and the core may be permanently deformed or so weakened as to render a roll unusable after being dropped or otherwise mishandled.
To avert the need for costly discarding of rolls having damaged cores, past practices have involved efforts to repair the damaged core or to modify roll handling machinery such that the roll can be used thereon despite its damaged core. In the former practice, cores have sometimes been straightened manually by driving a metal mandrel fully into the core and then removing the mandrel. This operation is time consuming and the straightened cores are sometimes so weakened that they collapse. In the latter practice, the conventional bobbin on which undamaged rolls are used is replaced by so-called "core stretcher". The stretcher is of lesser diameter than the bobbin diameter and, on receipt of the damaged roll, the stretcher is mechanically radially expanded to frictionally grip the damaged core. While the damaged roll may now be used on such core stretcher, this practice requires that at least one machine in each production line be equipped with a core stretcher and that all damaged rolls be run on that machine. So equipping a production line is costly and, even then, not all damaged rolls can be salvaged. Thus, rolls which cannot be accommodated by the core stretcher are unusable.